# LegacyBehaviors undefined ## Content Following are the breaking changes for LegacyBehaviors. | **API** | **Description** | | --- | ----------- | | **LegacyBehaviors.CalculationEngine** | By default, in Spread WinForms 12, the date time functions and formulas used in worksheets return the serial numeric values as results.  
However, if a user uses the LegacyBehaviors.CalculationEngine, the date time functions and formulas will return DateTime values instead of the serial numeric values. | | **LegacyBehaviors.PropertyDefaults** | By default, LegacyBehaviors.PropertyDefaults is turned off in V12. When this flag is turned off then there are some changes as compared with the older versions as described below-
  1. **Changes in default values for the following APIs**FpSpread.AllowUserFormulas = trueFpSpread.AllowDragDrop = trueFpSpread.AllowDragFill = trueFpSpread.AllowSheetMove = trueFpSpread.AllowEditOverflow = true FpSpread.BorderCollapse = BorderCollapse.CollapseFpSpread.ResizeZeroIndicator = trueFpSpread.TabStripPolicy = TabStripPolicy.AlwaysSheetView.SelectionPolicy = SelectionPolicy.MultiRangeSheetView.AutoFilterMode = AutoFilterMode.EnhancedContextMenuSheetView.Protect = false and Cell.Locked = true (same with V11J but different from V10 and lower versions)
  2. **Changes during keyboard navigation**Pressing the "F2" key will start editing with current cell value.Pressing "Backspace" key will start editing with empty editor.Pressing the "F4" key takes no effect.When a user presses an input key to start editing, the current cell value will be replaced by the pressed key.
|